<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <script>
      'use strict';

      var person = {
        name: "zhangjz",
        age: 15,
        email: "163@qq.com",
        score: 0
      }
  </script>
</head>
<body>

<!--

console.log(person.age);
VM240:1 15
undefined
console.log(person.constructor);
VM262:1 ƒ Object() { [native code] }
undefined
console.log(person.toString);
VM318:1 ƒ toString() { [native code] }
undefined
console.log(person.score);
VM372:1 0
undefined
person.name="zjz";
"zjz"
console.log(person.name);
VM458:1 zjz
undefined
person.aaaaaaaaaaaaa
undefined
person
{name: "zjz", age: 15, email: "163@qq.com", score: 0}age: 15email: "163@qq.com"name: "zjz"score: 0__proto__: Objectconstructor: ƒ Object()hasOwnProperty: ƒ hasOwnProperty()isPrototypeOf: ƒ isPrototypeOf()propertyIsEnumerable: ƒ propertyIsEnumerable()toLocaleString: ƒ toLocaleString()toString: ƒ toString()valueOf: ƒ valueOf()__defineGetter__: ƒ __defineGetter__()__defineSetter__: ƒ __defineSetter__()__lookupGetter__: ƒ __lookupGetter__()__lookupSetter__: ƒ __lookupSetter__()get __proto__: ƒ __proto__()set __proto__: ƒ __proto__()
person.newProperty = "15";
"15"
person
{name: "zjz", age: 15, email: "163@qq.com", score: 0, newProperty: "15"}
delete person.score
true
person
{name: "zjz", age: 15, email: "163@qq.com", newProperty: "15"}
"name" in person
true
person.hasOwnProperty(name);
false
person.hasOwnProperty("age");
true
person.hasOwnProperty("newProperty");
true
person.hasOwnProperty("toString");
false

-->
</body>
</html>